66 research outputs found

    Anhydrous proton conducting polymer electrolyres based on polymeric ionic liquids

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    Anhydrous proton conducting polymer electrolytes based on polymeric ionic liquids

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    Imidazolium types of ionic liquids were immobilized by tethering it to acrylate backbone. These imidazolium salt containing acrylate monomers were polymerize at 70oC by free radical polymerization to give polymers poly(AcIm-n) with n being the side chain lenght. The chemical structure of the polymer electrolytes obtained by the described synthetic routes was investigated by NMR-spectroscopy. The polymers were doped with various amounts of H3PO4 and LiN(SO2CF3)2, to obtain poly(AcIm-n) x H3PO4 and poly(AcIm-2-Li) x LiN(SO2CF3)2. The TG curves show that the polymer electrolytes are thermally stable up to about 200◦C. DSC results indicates the softening effect of the length of the spacers (n) as well as phosphoric acid. The proton conductivity of the samples increase with x and reaches to 10-2 Scm-1 at 120oC for both poly(AcIm-2)2H3PO4 and poly(AcIm-6)2H3PO4. It was observed that the lithium ion conductivity of the poly(AcIm-2-Li) x LiN(SO2CF3)2 increases with blends (x) up to certain composition and then leveled off independently from blend content. The conductivity reaches to about 10-5 S cm-1 at 30oC and 10-3 at 100oC for poly(AcIm-2-Li) x LiN(SO2CF3)2 where x is 10. The phosphate and phosphoric acid functionality in the resulting polymers, poly(AcIm-n) x H3PO4, undergoes condensation leading to the formation of cross-linked materials at elevated temperature which may improve the mechanical properties to be used as membrane materials in fuel cells. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to obtain information about hydrogen bonding in solids. The low Tg enhances molecular mobility and this leads to better resolved resonances in both the backbone region and side chain region. The mobile and immobile protons can be distinguished by comparing 1H MAS and 1H-DQF NMR spectra. The interaction of the protons which may contribute to the conductivity is observed from the 2D double quantum correlation (DQC) spectra

    High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

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    Transport and Electro-Optical Properties in Polymeric Self-Assembled Systems

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    Anhydrous proton conducting polymer electrolytes based on polymeric ionic liquids

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    Imidazolium types of ionic liquids were immobilized by tethering it to acrylate backbone. These imidazolium salt containing acrylate monomers were polymerize at 70oC by free radical polymerization to give polymers poly(AcIm-n) with n being the side chain lenght. The chemical structure of the polymer electrolytes obtained by the described synthetic routes was investigated by NMR-spectroscopy. The polymers were doped with various amounts of H3PO4 and LiN(SO2CF3)2, to obtain poly(AcIm-n) x H3PO4 and poly(AcIm-2-Li) x LiN(SO2CF3)2. The TG curves show that the polymer electrolytes are thermally stable up to about 200◦C. DSC results indicates the softening effect of the length of the spacers (n) as well as phosphoric acid. The proton conductivity of the samples increase with x and reaches to 10-2 Scm-1 at 120oC for both poly(AcIm-2)2H3PO4 and poly(AcIm-6)2H3PO4. It was observed that the lithium ion conductivity of the poly(AcIm-2-Li) x LiN(SO2CF3)2 increases with blends (x) up to certain composition and then leveled off independently from blend content. The conductivity reaches to about 10-5 S cm-1 at 30oC and 10-3 at 100oC for poly(AcIm-2-Li) x LiN(SO2CF3)2 where x is 10. The phosphate and phosphoric acid functionality in the resulting polymers, poly(AcIm-n) x H3PO4, undergoes condensation leading to the formation of cross-linked materials at elevated temperature which may improve the mechanical properties to be used as membrane materials in fuel cells. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to obtain information about hydrogen bonding in solids. The low Tg enhances molecular mobility and this leads to better resolved resonances in both the backbone region and side chain region. The mobile and immobile protons can be distinguished by comparing 1H MAS and 1H-DQF NMR spectra. The interaction of the protons which may contribute to the conductivity is observed from the 2D double quantum correlation (DQC) spectra

    Temperature and Frequency Dependence on Electrical Properties of Fe3O4@ Caffeic Acid Nanocomposite

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    Substances naturelles antipaludiques (mise au point d'une méthode de détection des adduits hème-molécules par spectrométrie de masse)

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    Le paludisme est l'une des plus meurtrières de toutes les affections humaines. Bien qu'endémique des pays dits " en voie de développement ", bon nombre de chercheurs occidentaux ont choisi de s'investir dans cette lutte. En effet, seule la découverte de nouvelles thérapeutiques, peu coûteuses et facilement accessibles, permettra d'enrayer le développement mortel de cette affection parasitaire. Après avoir présenté la maladie, ce mémoire s'attache à décrire les récents efforts menés sur la découverte de nouvelles cibles antipaludéennes ainsi que les substances naturelles s'étant révélées actives sur les Plasmodium. Des travaux personnels destinés à détecter, par spectrométrie de masse, les substances naturelles susceptibles de former des adduits avec l'hème, sont présentés. Les premiers résultats obtenus sur des extraits de quinquina et d'armoise annuelle, montrent qu'il est possible de détecter, directement dans un extrait total de plante, les composés formant des liaisons avec l'hème.TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF
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